Experimental Research Articles

Synergistic Impact on Indoor Air Quality: The Combined Use of Air Conditioners, Air Purifiers, and Fresh Air Systems

As concerns about indoor air quality increase, air purifiers and fresh air systems are increasingly being used in conjunction with air conditioners in office buildings. To study the synergistic effects of multisystem joint operation on indoor air quality, this study used a combination of experimental and simulation methods to study the indoor particulate matter with a diameter of less than 2.5 µm (PM2.5) and carbon dioxide (CO2) concentrations under different operation conditions. The purification time and the PM2.5 concentration distribution under different conditions were compared with the condition in which the purifier was used alone. The results showed that the purification time required for the condition that the air conditioner runs together with the purifier was shortened by 15.2%. When the fresh air system is running together with the purifier, the purification time can be reduced by 30.4%. It was reduced by 32.6% when the three systems were operating at the same time. The PM2.5 concentration distribution under the joint operating condition was much more even than that under the condition in which the purifier was running alone. To analyze the impact on the CO2 distribution, the CO2 distributions under different joint operations were compared. The results show that the fresh air system can effectively dilute CO2 below 1000 ppm in 30 min. The air conditioner and purifier could help to mix the indoor air to provide a much more uniform indoor CO2 distribution.

A foundation model enhanced approach for generative design in combinational creativity

In creativity theory, combining two unrelated concepts into a novel idea is a common means of enhancing creativity. Designers can integrate the Additive concept into the Base concept to inspire and facilitate creative tasks. However, conceiving high-quality combinational ideas poses a challenge that combinational creativity itself demands the consideration of conceptual reasoning and synthesis. We propose an AI foundation model enhanced approach for supporting combinational creativity. This approach derives combinational embodiments, and assists humans in verbalising and externalising combinational ideas. Our experimental study demonstrates that the generated combinational ideas by the approach obtained highest scores compared to those ideas generated without an AI foundation model or combinational strategy. We built a combinational creativity tool called CombinatorX based on this approach to generate ideas. In a study with the comparison of an existing combinational creativity tool and Internet search, we validated that our approach improves the effectiveness of combinational idea generation, enables a reduction in labour force, and facilitates the refinement of combinational ideation.

Experimental investigation of 3D printed polylactic acid and polylactic acid – hydroxyapatite composite through material extrusion technique for biomedical application

In biomedical industries, composite additive manufacturing are employed for customization, quicker production, efficient use and capital reduction. This experimental work focuses on the development of poly lactic acid (PLA) and novel extruded hydroxyapatite (HA) reinforced poly lactic acid (HPLA) by material extrusion (ME) technique and their properties were compared with that of standard 3D printed PLA. The extruded composite filaments were subjected to thermal characterization (DSC, TGA) and chemical characterization (FTIR) to ensure filament quality and its implementation in ME technique for 3D printing process. In addition, the melt compounded composite filaments were subjected to annealing to observe the influence of heat treatment upon their mechanical properties and thereby to validate their potential to resist breakage during ME process. Taguchi orthogonal array method using MiniTab software is employed to execute the parameter optimization for the 3D printing process. The 3D printed tensile, flexural and impact specimens, using pure PLA and extruded composite filaments, as per American Society for Testing and Materials (ASTM) standards were subjected to a comparative experimental study which showed that 3D printed specimens using PLA and HPLA performed better than that of standard PLA specimens due to the improvement in their crystalline nature. The ruptured specimens were subjected to microstructural characterization (optical microscopy, SEM) to observe failure modes and ash content test was conducted to validate the homogenous distribution HA filler particles in PLA matrix. In addition, mechanical characterization was also performed on 3D printed bone plate/bone scaffold application using extruded filaments of PLA and HPLA, as per ASTM F543 standards, to validate incorporation of the composite filaments in real-time application in biomedical industry.

An overview of mycotoxicoses in rabbits.

Mycotoxicoses are usually a consideration in large animal species but can affect companion animals as well. Due to increasing interest and the ease of using rabbits as laboratory models, a growing number of published experimental studies discuss the effects of various mycotoxins on this species. However, the available evidence is fragmented and heterogeneous, and has not recently been collated in a review, to my knowledge. Although mycotoxicoses in rabbits are typically subclinical, clinical signs can include weight loss, anorexia, gastrointestinal disorders, stunted growth, reproductive abnormalities, and susceptibility to infections. An antemortem diagnosis typically relies on a comprehensive clinical history, and assessment of clinical signs and relevant laboratory findings, with confirmation of exposure achieved through the measurement of mycotoxin concentrations in feed or target organs. My review focuses on the clinicopathologic and histopathologic effects of the mycotoxins most important in rabbits, including fumonisins, ochratoxins, aflatoxins, trichothecenes, and zearalenone. This review offers a thorough overview of the effects of mycotoxins in rabbits, serving as a one-stop resource for veterinary practitioners, diagnosticians, and researchers.

Modulating the Electrolyte Microenvironment in Electrical Double Layer for Boosting Electrocatalytic Nitrate Reduction to Ammonia.

Electrochemical nitrate reduction reaction (NO3RR) is a promising approach to achieve remediation of nitrate-polluted wastewater and sustainable production of ammonia. However, it is still restricted by the low activity, selectivity and Faraday efficiency for ammonia synthesis. Herein, we propose an effective strategy to modulate the electrolyte microenvironment in electrical double layer (EDL) by mediating alkali metal cations in the electrolyte to enhance the NO3RR performance. Taking bulk Cu as a model catalyst, the experimental study reveals that the NO3--to-NH3 performance in different electrolytes follows the trend Li+ < Cs+ < Na+ < K+. Theoretical studies illustrate that the proton transport rate in NO3RR and the activity of the rate-determining step (NO3- to NO2-) increase in the order Li+ < Cs+ < Na+ < K+. The cation effects are also general for two typical nanostructured catalysts including copper/cuprous oxide and nickel phosphides, achieving near-100% Faradaic efficiency and over 99% conversion of NO3- to NH3. Furthermore, we demonstrate that NO3- can be converted to high-purity NH4Cl by copper/cuprous oxide catalyst in K+-containing electrolyte.

Product-specific reaction kinetics in continuous uniform supersonic flows probed by chirped-pulse microwave spectroscopy.

Experimental studies of the products of elementary gas-phase chemical reactions occurring at low temperatures (<50K) are very scarce, but of importance for fundamental studies of reaction dynamics, comparisons with high-level quantum dynamical calculations, and, in particular, for providing data for the modeling of cold astrophysical environments, such as dense interstellar clouds, the atmospheres of the outer planets, and cometary comae. This study describes the construction and testing of a new apparatus designed to measure product branching fractions of elementary bimolecular gas-phase reactions at low temperatures. It combines chirped-pulse Fourier transform millimeter wave spectroscopy with continuous uniform supersonic flows and high repetition rate laser photolysis. After a comprehensive description of the apparatus, the experimental procedures and data processing protocols used for signal recovery, the capabilities of the instrument are explored by the study of the photodissociation of acrylonitrile and the detection of two of its photoproducts, HC3N and HCN. A description is then given of a study of the reactions of the CN radical with C2H2 at 30K, detecting the HC3N product, and with C2H6 at 10K, detecting the HCN product. A calibration of these two products is finally attempted using the photodissociation of acrylonitrile as a reference process. The limitations and possible improvements in the instrument are discussed in conclusion.

A scoping review on the use of traditional medicine and oral health in Africa.

This review aimed to chart the landscape of literature concerning the precise applications of traditional medicine in managing specific oral diseases and, in doing so, to pinpoint knowledge gaps surrounding the use of traditional medicine for oral disease management in the African context. A systematic search of the literature was conducted on PubMed, Web of Science, Scopus, and CINAHL. The search was conducted from the inception of the database till September 2023. A search of related citations and references was also carried out. Only English language publications were included. A summary of studies that met the inclusion criteria was conducted. Of the 584 records identified, 11 were duplicates and 12 studies, published between 2006 and 2021, met the inclusion criteria. The studies were published from eight countries located in the five sub-regions on the continent. All the studies were either experimental designs or ethnobotanical surveys and they all utilized plant-based remedies. The five experimental studies aimed to assess the impact of whole plants or plant extracts on the three microorganisms responsible for dental caries and seven responsible for periodontal diseases. The number of plant species identified by the seven ethnobotanical surveys ranged from 29 to 62 while the number of plan families ranged from 15 to 29. The remedies were either topical applied, use as mouth rinses, gargled, or chewed. The systemic routes of administration identified were inhalation and drinking. The remedies were used for the treatment of hard such as dental caries and tooth sensitivity, to soft tissue lesions such as mouth ulcers, gingival bleeding, and mouth thrush. Other oral disorders managed include halitosis, jaw fracture, and oral cancer. Given the increasing prevalence of oral diseases within the region, the shortage of oral healthcare professionals and limited access to financial resources, it becomes imperative to support the generation of empirical evidence to enhance the provision of traditional medicine for oral healthcare in Africa.

Understanding the Red Shift in the Absorption Spectrum of the FAD Cofactor in ClCry4 Protein.

It is still a puzzle that has not been entirely solved how migratory birds utilize the Earth's magnetic field for biannual migration. The most consistent explanation thus far is rooted in the modulation of the biological function of the cryptochrome 4 (Cry4) protein by an external magnetic field. This phenomenon is closely linked with the flavin adenine dinucleotide (FAD) cofactor that is noncovalently bound in the protein. Cry4 is activated by blue light, which is absorbed by the FAD cofactor. Subsequent electron and proton transfers trigger radical pair formation in the protein, which is sensitive to the external magnetic field. An important long-lasting redox state of the FAD cofactor is the signaling (FADH•) state, which is present after the transient electron transfer steps have been completed. Recent experimental efforts succeeded in crystallizing the Cry4 protein from Columbia livia (ClCry4) with all of the important residues needed for protein photoreduction. This specific crystallization of Cry4 protein so far is the only avian cryptochrome crystal structure available, which, however, has great similarity to the Cry4 proteins of night migratory birds. The previous experimental studies of the ClCry4 protein included the absorption properties of the protein in its different redox states. The absorption spectrum of the FADH• state demonstrated a peculiar red shift compared to the photoabsorption properties of the FAD cofactor in its FADH• state in other Cry proteins from other species. The aim of this study is to understand this red shift by employing the tools of computational microscopy and, in particular, a QM/MM approach that relies on the polarizable embedding approximation.

An experimental study of foam-oil interactions for nonionic-based binary surfactant systems under high salinity conditions

A key factor affecting foam stability is the interaction of foam with oil in the reservoir. This work investigates how different types of oil influence the stability of foams generated with binary surfactant systems under a high salinity condition. Foam was generated with binary surfactant systems, one composed of a zwitterionic and a nonionic surfactant, and the other composed of an anionic and a nonionic surfactant. Our results showed that the binary surfactant foams investigated are more tolerant under high salinity conditions and in the presence of oil. This was visually observed in our microscopic analysis and was further attributed to an increase in apparent viscosity achieved with binary surfactant systems, compared to single surfactant foams. To understand the influence of oil on foam stability, we performed a mechanistic study to investigate how these oils interact with foams generated with binary surfactants, focusing on their applicability under high salinity conditions. The generation and stability of foam are linked to the ability of the surfactant system to solubilize oil molecules. Oil droplets that solubilize in the micelles appear to destabilize the foam. However, oils with higher molecular weights are too large to be solubilized in the micelles, hence the molecules will have less ability to be transported out of the foam, so oil seems to stabilize the foam. Finally, we conducted a multivariate analysis to identify the parameters that influenced foam stability in different oil types, using the experimental data from our work. The results showed that the oil molecular weight, interfacial tension between the foaming liquid and the oil, and the spreading coefficient are the most important variables for explaining the variation in the data. By performing a partial least square regression, a linear model was developed based on these most important variables, which can be used to predict foam stability for subsequent experiments under the same conditions as our work.

Study on triaxial compression performance and damage characteristics of fiber-reinforced ecological matrix cementing gangue gypsum fill material.

Polypropylene fiber was equally mixed into alkali-activated slag fly ash geopolymer in order to ensure the filling effect of mine goaf and improve the stability of cemented gangue paste filling material with ecological matrix. Triaxial compression tests were then conducted under various conditions. The mechanical properties and damage characteristics of composite paste filling materials are studied, and the damage evolution model of paste filling materials under triaxial compression is established, based on the deviatoric stress-strain curve generated by the progressive failure behavior of samples. Internal physical and chemical mechanisms of the evolution of structure and characteristics are elucidated and comprehended via the use of SEM-EDS and XRD micro-techniques. The results show that the fiber can effectively improve the ultimate strength and the corresponding effective stress strength index of the sample within the scope of the experimental study. The best strengthening effect is achieved when the amount of NaOH is 3% of the mass of the solid material, the amount of fiber is 5‰ of the mass of the solid material, and the length of the fiber is about 12 mm. The action mode of the fiber in the sample is mainly divided into single-grip anchoring and three-dimensional mesh traction. As the crack initiates and develops, connection occurs in the matrix, where the fiber has an obvious interference and retardation effect on the crack propagation, thereby transforming the brittle failure into a ductile failure and consequently improving the fracture properties of the ecological cementitious coal gangue matrix. The theoretical damage evolution model of a segmented filling body is constructed by taking the initial compaction stage end point as the critical point, and the curve of the damage evolution model of the specimen under different conditions is obtained. The theoretical model is verified by the results from the triaxial compression test. We concluded that the experimental curve is in good agreement with the theoretical curve. Therefore, the established theoretical model has a certain reference value for the analysis and evaluation of the mechanical properties of paste filling materials. The research results can improve the utilization rate of solid waste resources.

The Environmental Impact of Exposure to Electromagnetic Fields (EMF) on Health

We have methodically scrutinized the pervasive electromagnetic fields (EMF) prevalent in modern society for their potential health hazards. The aim of this study was to investigate the levels of exposure to electromagnetic fields (EMF), resulting biological effects, present recommendations, population characteristics, and public opinion. The main aim of this research is to give a comprehensive explanation of the subject. The data collection process encompassed gathering EMF exposure levels in different settings, analyzing experimental studies on biological impacts, consolidating existing standards, investigating demographic discrepancies, and evaluating public perception through surveys. We analyzed the data using descriptive statistics to summarize the findings and inferential statistics to evaluate the relationships between variables. EMF exposure levels differed among various locations, with metropolitan areas and industrial facilities demonstrating elevated amounts. Studies in real life have shown that electromagnetic fields (EMF) can have many effects on living things, including increased oxidative stress, changed gene expression, and messed up biological cycles. Different organizations had varying guidelines, which were based on different risk assessment approaches. There were differences in the demographic groups regarding their exposure to electromagnetic fields (EMF) and their levels of awareness. Children and teenagers had more exposure to EMF, whereas younger individuals showed higher levels of awareness but variable degrees of concern. Public opinion differed among age groups, with younger people relying more on online sources for information. This study offers significant insights into the complex correlation between electromagnetic field (EMF) exposure and human health. The results emphasize the necessity of focused evaluation of risks and implementation of measures to reduce them, standardization of standards, and customized communication campaigns to tackle demographic differences in awareness and apprehension. This research contributes new findings to the existing body of knowledge, facilitating public discussions, influencing governmental decisions, and fostering a healthier and more informed society.

The Effect of Greeting Card Media on Students’ Writing Skill

The research was aimed to know about the effect of greeting card media on students’ ability in writing of eighth grade at junior high school in Bangka Belitung. This experimental study employed quasi experimental design. The samples used was the 8th grade students of high school many as 54 students. The research used a writing test as a data collection technique. In the technique of analyzing the data, the research used t-test was in the form of paired sample t-test to test the hypothesis through the SPSS. The finding showed an improvement in students' writing when they used greeting card media. The result of t-obtained 5.712 was greater than the t-table 2.007. The result of 2-tailed significance 0,00 have less score than 0,05. Thus, it menas that the experimental group had a greater performance than the control group.

Exploring the influence of instagram use on materialism and situational intrinsic learning motivation: An online experimental study

AbstractIn recent years, social media such as YouTube, TikTok, and Instagram have become an essential part of the everyday lives of children and young adults. Integrating elements of these social media into higher education may have the potential to enhance situational intrinsic learning motivation through the emotional design and proximity to students' lives, but this also poses the risk of fostering a situational materialistic focus due to the ubiquitous materialistic content on especially Instagram, undermining situational intrinsic learning motivation. In the present study, we examined if the primary use of Instagram is associated with higher materialism and how exposure to Instagram-framed pictures influences situational intrinsic learning motivation. The current study conducted an online experiment. Participants (N = 148) were randomly assigned to one of three groups after they rated items about general and problematic social media use and materialism. In the first two groups, participants were asked to rate the pleasantness of luxury or nature Instagram-framed pictures. A third group received no pictures. Afterwards, the situational intrinsic learning motivation was assessed through a mock working task. The findings prove that people who (primarily) use Instagram tend to be more materialistic than people who (primarily) use another social medium and that exposure to Instagram-framed pictures neither positively nor negatively influenced situational intrinsic learning motivation but moderated the relationship between problematic social media use and situational intrinsic learning motivation. Limitations, implications, and future directions for social media use inhigher education are discussed.

A conservative approach to localize loose implant screw through cemented crown: an in vitro experimental study

BackgroundRetrieval of cement-retained implant-supported restorations is intriguing in cases of screw loosening. Detecting the estimated size of the screw access hole (SAH) could decrease destruction to the prosthesis and preserve the crown.ObjectivesTo precisely localize loose implant screws through cemented crowns to reduce crown damage after screw loosening.Materials and methodsIn this in vitro study, 60 cement-retained implants supported 30 zirconia-based, and 30 ceramics fused to metal (CFM) lower molar crowns were invented, and each was subdivided into three subgroups (10 each). In group I (AI/BI) (control), SAH was created with the aid of orthopantomography (OPG). In contrast, in group II (zirconia-crown), SAH was created with the aid of CBCT + 3D printed surgical guide with a 2 mm metal sleeve in subgroups IIA/IIIA and CBCT + MAR was used to develop SAH in subgroups IIB/IIIB. SEM and Micro-CT scanned the SAH openings to determine the diameter of the hole, cracking, chipping, and chipping volume.ResultsRegarding the effect of plane CBCT and CBCT + MAR on prepared crowns, a highly significant association between group I with group II (p = 0.001) and group III (p = 0.002) was detected. Regarding the cracking of SAH, significant differences between the zirconium crown and CFM restoration (p = 0.009) were found, while for the chipping, no significant association was seen between groups (p = 0.19).ConclusionsCBCT, either as a plane CBCT or with MAR, significantly improved the accuracy of drilling the screw channel and decreased injury to the existing restoration and abutment, aiding in better localization of SAH in loosened implant abutment screws.

Effects of eLearning Formats on Student Teachers’ Knowledge and Attitude Towards Evidence-Based Instruction

University teacher education aims at developing sustained knowledge and positive attitudes towards evidence-based instructional concepts. This experimental study examined (a) if two e-learning formats help develop sustained knowledge and positive attitudes towards evidence-based reading instruction, (b) if self-regulative principles can boost these effects, and (c) if effects are moderated by learner characteristics (namely prior knowledge, self-efficacy, learning preferences). N = 100 student teachers participated in one of two different e-learning formats on evidence-based reading instruction. While one group attended an e-learning course with self-regulative elements (adaptivity and feedback), the other group watched an e-lecture without these self-regulative elements. In both groups, participants showed positive attitudes and mastery of declarative knowledge, as the majority reached a minimum of 80% in criterion-oriented tests. However, participants’ procedural knowledge was less pronounced. A MANOVA showed no significant group differences between the e-learning course with self-regulative elements and the e-lecture without self-regulative elements with regard to knowledge and attitude acquisition. Path analyses displayed that individual learner characteristics (prior knowledge, self-efficacy, learning preferences) had an impact on attitudes, but not on knowledge acquisition. Implications for university education are discussed in the context of combining e-learning formats with face-to-face courses to also achieve mastery of procedural knowledge and to strengthen the effect of self-regulative elements.

The Study of Light as an Experimental Factor in Observing the Development of Children’s Artistic Abilities in Kindergarten

Playing with light and shadow is an inexhaustible stimulus for preschool children to develop divergent thinking and artistic expression. Creativity develops through artistic expression, and the experience enriches and matures thematically through the more conscious use of artistic language. The aim of the experimental study was to measure the level of artistic development in children aged five and six years. The level of creative, optical-thematic and artistic development was observed. In the study, two different programmes with implemented activities (experimental factors) were planned and compared with a control group. The first programme (experimental factor EP1) was described as modern and adapted to the children’s interests and incentives, while the second programme (experimental factor EP2) was prepared in advance and called traditional. A total of 161 children aged five and six years took part in the study. In order to measure the level of general artistic development, test drawings were made at the beginning and end of the experiment. These were analysed by a team of experts according to the aforementioned developmental aspects. The results of the experimental group with the traditional approach showed a statistically significantly higher performance in monitoring creative development than the control group. Within the two experimental programmes, the children in the EP1 programme achieved statistically better results in the aspect of creative development than the children in the EP2 programme. The results show that a well-designed programme for playing with light and shadow can have a positive effect on children’s artistic development.

Investigation of Frequency-Dependent Characteristics of Wire Rope under Tension Based on Transfer Function Method

Wire rope is a complex structure made by twisting wires of various sizes in the longitudinal direction. It is used to support or move engineering structures and is subject to various tensions. Dynamic properties are important parameters to evaluate the resistance to bending deformation and vibration reduction of various structures. They are affected by the magnitude of tension. In this study, an experimental method for measuring the frequency-dependent characteristics of wire rope under tension is proposed. The study analyzed flexural wave propagation employing a vibration transfer function. Experimental results showed that the transfer function of wire rope under tension is affected by tension and bending stiffness. The Newton–Raphson method was employed to numerically measure wavenumbers of the wire rope. The bending stiffness and loss factor were determined from the wavenumbers. Changes in the bending stiffness and loss factor as the tension increased were explained by the dynamic behavior of the structure under tension. As the tension increased, the bending stiffness increased, and the loss factor decreased. Hysteresis analysis indicated that the energy dissipation of wire rope is greater than that of a steel beam due to the friction between the wires. Statistical analysis confirmed a significant correlation between dynamic characteristics and tension in wire rope.

REM sleep preserves affective response to social stress - experimental study.

Sleep's contribution to affective regulation is insufficiently understood. Previous human research has focused on memorizing or rating affective pictures and less on physiological affective responsivity. This may result in overlapping definitions of affective and declarative memories, and inconsistent deductions for how rapid eye movement sleep (REMS) and slow-wave sleep (SWS) are involved. Literature associates REMS theta (4-8Hz) activity with emotional memory processing, but its contribution to social stress habituation is unknown.Applying selective sleep stage suppression and oscillatory analyses, we investigated how sleep modulated affective adaptation towards social stress and retention of neutral declarative memories. Native Finnish participants (N=29, age M=25.8y) were allocated to REMS or SWS suppression conditions. We measured physiological (skin conductance response, SCR) and subjective stress response and declarative memory retrieval three times: before laboratory night, the next morning, and after three days. Linear mixed models were applied to test the effects of condition and sleep parameters on emotional responsivity and memory retrieval.Greater overnight increase in SCR towards the social stressor emerged after suppressed SWS (intact REMS) relative to suppressed REMS (20.1% vs. 6.1%, p=.016). The overnight SCR increase was positively associated with accumulated REMS theta energy irrespective of the condition (r=.601, p=.002). Subjectively rated affective response and declarative memory recall were comparable between the conditions.The contributions of REMS and SWS to habituation of social stress are distinct. REMS theta activity proposedly facilitates the consolidation of autonomic affective responses. Declarative memory consolidation may not have greater dependence on intact SWS relative to intact REMS.Significance statement Disrupted sleep is a common problem with negative effects on affective regulation. While research indicates that rapid eye movement sleep has a central role in off-line affective processing, the mechanisms are not well defined. We used selective sleep stage suppression to investigate how disrupted sleep and stage-specific neural activity modulated the affective responsivity towards a self-conscious stressor inducing shame. We show that theta band oscillatory activity during rapid eye movement sleep is especially important for preserving the physiological stress response overnight. Understanding sleep-driven affective regulation facilitates development of applications aiming at improving mental wellbeing.

Inhibition of Mild Steel Corrosion by New Epoxy Resin in 1 M HCl: Synthesis, Characterization, Experimental Study and Theoretical Approach

Inhibition of Mild Steel Corrosion by New Epoxy Resin in 1 M HCl: Synthesis, Characterization, Experimental Study and Theoretical Approach

Experimental study on spray in the atmospheric surface layer by raindrops impacting water surface

Experimental study on spray in the atmospheric surface layer by raindrops impacting water surface